Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753030AbdC0JzF (ORCPT ); Mon, 27 Mar 2017 05:55:05 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:63436 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752701AbdC0Jrc (ORCPT ); Mon, 27 Mar 2017 05:47:32 -0400 From: Kishon Vijay Abraham I To: Bjorn Helgaas , Joao Pinto , , , , , , CC: , , Subject: [PATCH v5 15/24] PCI: dwc: dra7xx: Workaround for errata id i870 Date: Mon, 27 Mar 2017 15:15:11 +0530 Message-ID: <20170327094520.3129-16-kishon@ti.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170327094520.3129-1-kishon@ti.com> References: <20170327094520.3129-1-kishon@ti.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2626 Lines: 87 According to errata i870, access to the PCIe slave port that are not 32-bit aligned will result in incorrect mapping to TLP Address and Byte enable fields. Accessing non 32-bit aligned data causes incorrect data in the target buffer if memcpy is used. Implement the workaround for this errata here. Signed-off-by: Kishon Vijay Abraham I --- drivers/pci/dwc/pci-dra7xx.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c index 35c18534469c..79fb213e4877 100644 --- a/drivers/pci/dwc/pci-dra7xx.c +++ b/drivers/pci/dwc/pci-dra7xx.c @@ -26,6 +26,8 @@ #include #include #include +#include +#include #include "pcie-designware.h" @@ -528,6 +530,46 @@ static const struct of_device_id of_dra7xx_pcie_match[] = { {}, }; +/* + * dra7xx_pcie_ep_unaligned_memaccess: workaround for AM572x/AM571x Errata i870 + * @dra7xx: the dra7xx device where the workaround should be applied + * + * Access to the PCIe slave port that are not 32-bit aligned will result + * in incorrect mapping to TLP Address and Byte enable fields. Therefore, + * byte and half-word accesses are not possible to byte offset 0x1, 0x2, or + * 0x3. + * + * To avoid this issue set PCIE_SS1_AXI2OCP_LEGACY_MODE_ENABLE to 1. + */ +static int dra7xx_pcie_ep_unaligned_memaccess(struct device *dev) +{ + int ret; + struct device_node *np = dev->of_node; + struct of_phandle_args args; + struct regmap *regmap; + + regmap = syscon_regmap_lookup_by_phandle(np, + "ti,syscon-unaligned-access"); + if (IS_ERR(regmap)) { + dev_dbg(dev, "can't get ti,syscon-unaligned-access\n"); + return -EINVAL; + } + + of_parse_phandle_with_args(np, "ti,syscon-unaligned-access", + "#syscon-cells", 0, &args); + if (args.args_count != 2) { + dev_err(dev, "does not conform to #syscon-cells\n"); + return -EINVAL; + } + + ret = regmap_update_bits(regmap, args.args[0], args.args[1], + args.args[1]); + if (ret) + dev_err(dev, "failed to enable unaligned access\n"); + + return ret; +} + static int __init dra7xx_pcie_probe(struct platform_device *pdev) { u32 reg; @@ -644,6 +686,11 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev) case DW_PCIE_EP_TYPE: dra7xx_pcie_writel(dra7xx, PCIECTRL_TI_CONF_DEVICE_TYPE, DEVICE_TYPE_EP); + + ret = dra7xx_pcie_ep_unaligned_memaccess(dev); + if (ret) + goto err_gpio; + ret = dra7xx_add_pcie_ep(dra7xx, pdev); if (ret < 0) goto err_gpio; -- 2.11.0